1. Field of the Invention
The present invention relates to a printer apparatus that prints an image on a recorded material such as a recording sheet based on image information and to a cassette or a cartridge as consumables thereof.
2. Description of the Related Art
A printer apparatus as an output apparatus for a computer and a digital video output apparatus can be classified corresponding to recording systems into a thermal transfer printer apparatus, an ink jet printer apparatus, a laser printer apparatus and a wire dot printer apparatus. Among these printer apparatuses, the line thermal transfer printer apparatus employs ink sheets and recording sheets, selectively drives a plurality of heating elements arrayed in a main scan direction and thus conveys the ink sheet and the recording sheet in a sub-scan direction, thereby printing an image in dot lines on the recording sheet. Over the recent years, with advancements of input devices handling the images such as a digital camera, a digital video camera and a scanner as input side devices, the thermal transfer printer apparatus is increasingly focused. The thermal transfer printer apparatus is suited to printing and outputting, via a computer or a recording medium, electronic image information captured by a still camera recording a statistic image and a video camera.
Other types of printer apparatuses such as the ink jet printer apparatus have no alternative but to select binary values showing whether a dot is formed or not, and therefore obtain an apparent resolution and an apparent gradation by a method such as an error diffusion method while forming minute dots on the recording sheet. By contrast, the thermal transfer printer apparatus can easily change a heat value enabling one pixel to be controlled and is therefore capable of taking more of gradations about one pixel. Accordingly, the thermal transfer printer apparatus has an advantage of its being capable of acquiring smoother and higher-quality images than by other types of printer apparatuses such as the ink jet printer apparatus. The thermal transfer printer apparatus has improved performance of a thermal head serving as a recording unit and also improved performance of a material of a recoding sheet, and can therefore acquire an image print that is not inferior to a silver halide photo (print) in terms of a finishing quality level. As a result, the thermal transfer printer apparatus has been focused especially as a printer for natural images so as to match its stride to the advancements of the digital cameras over the recent years.
There is an advent of a system that performs direct printing and direct outputting without connecting the thermal transfer printer apparatus to the imaging devices such as the digital camera and the video camera. Another system is that the thermal transfer printer apparatus and the imaging device are integrally constructed, and the captured image information is directly printed and output with no intermediary of an image information processing device such as a computer. This type of system enables an easy photographic printout of the image information given from the digital camera and the digital video camera, and a much higher focus is placed on the thermal transfer printer apparatus. The thermal transfer type, however, needs to repeatedly transfer inks in plural colors in superposition in order to conduct full-color printing. A general construction for actualizing this full-color printing will hereinafter be described.
FIGS. 33A and 33B illustrate a first example of the general construction of the conventional thermal transfer printer. As illustrated in FIG. 33A, only an uppermost recording sheet P among the recording sheets P stacked in a recording sheet cassette 107 is separated and fed by a sheet feeding roller 108 and a separating member 109 and is conveyed to between a thermal head 104 and a platen roller 105. Ink sheet 106 is disposed between the thermal head 104 and the recording sheet P. The recording sheet P is wound along the periphery of the platen roller 105 having a slightly longer outer periphery than an entire length of the recording sheet P. The ink sheet 106 and the recording sheet P are brought into a press-contact with each other by the thermal head 104 and the platen roller 105. An ink on the ink sheet 106 is thermally transferred onto the recording sheet P by the heat emitted from the thermal head 104, and meanwhile the platen roller 105 is rotated, thereby performing the printing operation. For performing the next-color printing after finishing the first-color printing, as illustrated in FIG. 33B, the contact-pressure by the thermal head 104 is canceled. The recording sheet P is moved forward up to a print start position by further rotating the platen roller 105. The second and subsequent color printing is done by the same operation as of the first floor. Thus, the full-color printing is conducted in a way that superposes the three colors, yellow, magenta and cyan.
FIGS. 34A and 34B illustrate a second example of the general construction of the conventional thermal transfer printer. As illustrated in FIG. 34A, only the uppermost recording sheet P among the recording sheets P stacked in the sheet cassette 201 is separated and fed by the sheet feeding roller 202 and the separating member 203 and conveyed to a thermal head 204 and a platen roller 205. The ink sheet 206 and the recording sheet P are brought into the press-contact with each other by the thermal head 204 and the platen roller 205. An ink on the ink sheet 206 is thermally transferred onto the recording sheet P by the heat emitted from the thermal head 204, and meanwhile the recording sheet P is conveyed by a pair of rollers, i.e., a capstan roller 207 and a pinch roller 208, provided downstream in the printing direction, thus conducting the printing. Upon an end of the first color print, as illustrated in FIG. 34B, the press-contact by the thermal head unit 204 is canceled for performing the next-color printing. The recording sheet P is moved back to the print start position by rotating the capstan roller 207 and the pinch roller 208 in the directions opposite to those when performing the printing operation. Then, the recording sheet P undergoes the second and subsequent color printing by the same operation as of the first color. Thus, the full-color printing is performed in a way that superposes the three colors, yellow, magenta and cyan.
Also in the examples in FIGS. 33A, 33B, 34A and 34B, the recording sheets and the ink sheets within the sheet cassette are consumables, and need exchanging and replenishing according to how much the sheets are consumed. Herein, as to the ink sheets, it is a general practice, a user is supplied with a cartridge taking such a mode that both edges of the ink sheets are wound on two bobbins, and the two bobbins and the ink sheets are contained in a frame body. FIGS. 33A, 33B, 34A and 34B illustrate frame bodies 110 and 210 of the cartridge. The cartridge has air gap areas 110a and 210a as illustrated in FIGS. 33A, 33B, 34A and 34B. When loading the cartridge into the printer, the cartridge is guided and installed in a predetermined position so that the thermal heads 104, 204 provided in the printer body are fitted in the air gap areas 110a, 210a. 
The two types described above have been those conventional. The first example has demerits. One demerit is that the apparatus is to be upsized because of requiring the platen roller having a slightly longer outer periphery than an entire length of the recording sheet P. Another demerit is that the apparatus gets complicated because of requiring, though not illustrated in FIGS. 33A and 33B, a mechanism for winding the recording sheet along the periphery of the platen roller and thus holding the sheet-wound roller. The first example has, however, a merit enabling a speedup of print time due to no necessity of a period of time for returning the recording sheet as done in the second example because of the second-color print starting portion existing just posterior to the first-color printing portion upon terminating the first color printing. On the other hand, the second example has, though there is such a demerit that the printing time extends, a merit that facilitates downsizing and simplifying the apparatus.
The thermal transfer printer apparatus described above, however, involves using, as the recording sheet, a dedicated sheet having a surface that is easy to transfer the ink in order to acquire a preferable print. Therefore, a set of the ink cartridge containing the ink sheets for, e.g., fifty recording sheets and these recording sheets, is commercially available. As a result, the user takes a trouble to open a package of the recording sheets and the ink cartridge that are put on the market as a sheet-cartridge set and to employ the printer apparatus by loading the ink cartridge into a printer body and the recording sheets into the sheet cassette, respectively.
The thermal transfer printer, as illustrated in FIGS. 35A and 35B can lessen futility of the ink sheets by preparing different sizes of ink sheets corresponding to predetermined sizes of recording sheets. Accordingly, the commercially available sheet-cartridge sets are, e.g., a set of the A6-size recording sheets and the ink cartridge containing the ink sheets for the A6 size and a set of the A7-size recording sheets and the ink cartridge containing the ink sheets for the A7 size. The user purchases the sheet-cartridge set corresponding to each application. When performing the A7-size printing after the A6-size printing, the user takes out the A6-size recording sheets and the ink cartridge for the A6 size and loads, in place of this sheet-cartridge set, the A7-size recording sheets and the ink cartridge for the A7 size. Hereat, the taken-out A6-size recording sheets and ink cartridge for the A6 size need keeping for a later use. A trouble in this case is that the ink cartridge and the recording sheets are prepared separately and must be protected from being exposed to dusts and direct sunlight and be kept in storage bags.
Japanese Patent No. 2523355 and Japanese Patent Application Laid-Open No. 2000-108442 discuss cartridges (one of which is called a cassette in Japanese Patent Application Laid-Open No. 2000-108442) containing the ink sheets and the recoding sheets as an integral type by way of proposals for solving those troubles.
However, a construction of the thermal transfer printer discussed in Japanese Patent No. 2523355 is that the printing operation, though an ink sheet containing portion and a recording sheet containing portion are formed integrally, can not be conducted in a state where the ink sheets remain contained in the cartridge. Therefore, for conducting the printing operation, this thermal transfer printer requires a mechanism for taking the ink sheet out of the cartridge and loading the ink sheet up to a print position. Such a problem arises that the apparatus gets complicated to a degree corresponding to this mechanism and the reliability declines. A printer solving this problem is a thermal transfer printer discussed in Japanese Patent Application Laid-Open No. 2000-108442. A proposal thereof is that there is no necessity of loading the ink sheet up to the print position after housing the integral type cartridge into the printer body, and the printing operation can be conducted in an as-housed state. The construction makes the user be aware of neither the trouble of setting the ink sheets and the recording sheets separately in the printer apparatus nor the trouble of separately keeping the ink sheets and the recording sheets taken out on the occasion of using a different type of recording sheets. In the case of placing a first purpose on printing a photo, however, the sheets to be used require a predetermined thickness for ensuring a keeping quality, durability or a print quality. Hence, if extremely bent when conveyed for printing, the printing surface might be damaged or corrugated. If large of the thickness of the recording sheet and if there is no space area in which the recording sheet is given a sufficient flexure when separating the recording sheet, the reliability declines depending on a separation method of separating the single recording sheet from the cartridge. The cartridge discussed in Japanese Patent Application Laid-Open No. 2000-108442 has a contrivance of forming an external shape of the cartridge with “R” of a slightly large radius so as not to cause, though a sheet conveyance route is formed by an external peripheral surface of the cartridge, the extreme bending in order to restrain the sheet from being damaged and to increase the reliability on the conveyance. The inside of a circular arc for forming the conveyance route, however, turns out to be a futile space. A thicknesswise space of the cartridge is needed to a certain or larger degree in order to smoothen the bending of the conveyance route, and the downsizing reaches its limit. After all, the cartridge comes to have a size larger than required at the minimum for containing the recording sheets and the ink sheets, resulting in an upsized printer body.
It is to be noted that Japanese Patent Application Laid-Open No. H08-319036 discusses a construction scheming to raise the separation reliability of a pawl separating system and to keep constant a distance between a separating pawl and a pick-up roller even in the case of a different size of sheet. According to this system, an amount of engagement between the separating pawl and the sheet is invariably fixed, and the separation reliability can be ensured. This system is complicated in mechanism and leads to the upsized apparatus, resulting in a cost-up.